Endoscopic methods are commonly used for diagnosis and/or treatment of internal anatomical lumens within a patient's body, such as, for example, the gastrointestinal tract. For example, there are several methods, known as endoscopic mucosal resection, for treating both malignant and non-malignant tumors within a patient's mucosa (the mucous tissue lining various internal anatomical lumens consisting of epithelium, lamina, propria, and, in the gastrointestinal tract, a layer of smooth muscle). Endoscopic mucosal resection may include snaring and then excising sessile adenomas (i.e., tumors attached to a bodily surface) in an anatomical lumen. If the adenoma is flat against the lumen wall, thus making it difficult to snare and excise, one of several methods may be used to raise the flat adenoma so that it may be snared and excised. One method includes using forceps to raise the flat adenoma. Another method includes using a vacuum to raise the flat adenoma. A further method, called hydrodissection includes injecting fluid into the submucosa so as to create a pocket or opening below the tissue to raise the flat adenoma above the underlying tissue.
Once the adenoma is excised, bleeding into the body lumen may result from the underlying portion of the tissue from which the adenoma was removed. These, and other medical procedures (e.g., staining, marking, and identifying tissue), may involve making an incision in body tissue and controlling any consequent bleeding. When performing these procedures, it may be desirable to minimize both tissue trauma during incision and the time required to stop internal bleeding. In addition, it is desirable to cleanly cut and retrieve a uniform tissue sample of sufficient size particularly where a pathology study of the sample is necessary. Furthermore, it is desirable for the resection to leave clean margins at the treatment site in order to minimize any further disruption of the surrounding anatomy.
Minimally invasive or least invasive surgical techniques, such as laparoscopic, endoscopic, or arthoroscopic techniques, are sometimes used because body tissue is usually traumatized less by those techniques than by more invasive conventional techniques. Electrosurgical methodologies, sometimes used in conjunction with the minimally or least invasive techniques, allow the making of an incision and the stopping or stemming of bleeding with less attendant tissue trauma and greater control than do conventional modalities. While useful in stemming the flow of blood resulting from tissue resection, electrosurgical methods can often cause unnecessary burning or trauma beyond the desired treatment site and into the surrounding anatomical lumen wall during a resection procedure.
The aforementioned methods, while effective, have certain drawbacks. As physicians sometimes use different devices to perform different functions, for example, use one catheter to make an incision and another to perform hemostasis or irrigation, the exchange of catheters to provide different functions extends the time to complete therapy, increases the risk to the patient, and also increases patient discomfort. Consequently, physicians have to weigh the time, complexity, and benefits of interchanging single or dual purpose catheters to change treatment modalities against whatever disadvantage may result by working with a single catheter.
Thus, it is desirable to present a method for endoscopic mucosal resection that overcomes the disadvantages of the prior art to, as examples, retrieve a uniform tissue sample adequate for pathology study, maintain clean tissue margins, reduce trauma to the surrounding anatomy, and control the depth of burning attendant to electrosurgery.